1. Field of the Invention
The present invention relates to a structure of a connector of a light guide having a bundle of optical fibers for transmitting light energy from a light source.
2. Description the Prior Art
Light guides are widely used as means transmitting light energy from a light source to a target part, for example, in an endoscope.
FIG. 1 is a schematic view showing the endoscope for photographing a part of human body cavity and displaying an image of the photographed part on a monitor. In the figure, an endoscope apparatus 2 has a light source 10 for emitting light, which is collected by a condenser lens 12 and send to light receiving unit 14. The light is then transmitted to an illumination unit 18 through a light transmission unit 16, for illuminating a target part in a human body cavity. A sensor 22 photographs the target part and provides image informations to be processed by circuits such as 24, 26, 28 shown in FIG. 1. Processed signals are sent to a monitor from the circuits and then, the photographed image is displayed on a monitor 30.
The light transmitting unit 16 is usually a light guide comprising a bundle of optical fibers. Each optical fiber comprises a core transmitting light energy and a glass cladding around the core for preventing light leakage. The light guide 16 is usually accommodated in an inserting means which is inserted into along a human body cavity, so that the inserting means and light guide must be flexible. This requirement induces that the light guide should comprise a bundle of thin optical fiber elements.
From the view points of manufacturing, maintenance and handling, the light guide is preferred to be properly divided into sections and connected to one another with connectors. It is practically difficult, however, to provide a connector to each of a lot of the thin optical fiber elements. Then, optical fiber elements 40 are, as shown in FIG. 2, bonded together to form connectors 42, 42a or 42b. End faces of the connectors 42a and 42b are tightly attached to one another in order to transmit enough light energy.
However, since it is difficult to align each center axis of the optical fiber elements of opposing connectors 42a and 42b when attaching them to each other, a great deal of the light energy is lost. This light energy loss causes problems that it generates heat loss and requires a light source of a large power.